rollup.config.js

import fs from 'fs'
import { join } from 'path'
import url from 'url'

import babel from '@rollup/plugin-babel'
import resolve from '@rollup/plugin-node-resolve'
import terser from '@rollup/plugin-terser'
import virtual from '@rollup/plugin-virtual'

const dirname = url.fileURLToPath(new URL('.', import.meta.url))

// Global variable name for UMD build
const umdName = 'MediaInfo'

const srcDir = join(dirname, 'src')
const distDir = join(dirname, 'dist')
const esmBundleDir = join(distDir, 'esm-bundle')
const umdBundleDir = join(distDir, 'umd')

const mediaInfoModuleContent = fs
  .readFileSync(join(dirname, 'build', 'MediaInfoModule.browser.js'))
  .toString()

const makeOutput = (format, minify = false) => ({
  file: join(format === 'esm' ? esmBundleDir : umdBundleDir, `index${minify ? '.min' : ''}.js`),
  format,
  name: format === 'umd' ? umdName : undefined,
  plugins: minify ? [terser()] : undefined,
  sourcemap: 'inline',
})

export default {
  input: join(srcDir, 'index.ts'),
  output: ['esm', 'umd'].reduce(
    (acc, format) => [...acc, makeOutput(format), makeOutput(format, true)],
    []
  ),
  plugins: [
    resolve({ extensions: ['.ts'] }),

    // The module loader generated by emscripten is different for each environment.
    // For the bundler we just inject the correct content.
    virtual({ 'src/MediaInfoModule': mediaInfoModuleContent }),

    babel({
      babelHelpers: 'bundled',
      envName: 'ESM_ROLLUP',
      exclude: ['./node_modules/**', './src/cli.ts'],
      extensions: ['.ts'],
      include: ['./src/**'],
    }),
  ],
}